Dysregulated Serum Cytokine Production in Pediatric Patients with ß-Thalassemia Major.

ß-Thalassemia major (ß-TM) is an inherited disorder of hemoglobin (Hb) production, which can cause severe anemia. A compromised immune system has been observed in patients with ß-TM, whereas cytokines have a major role in immune modulation. Interleukin-4 (IL-4), IL-8, IL-13 and transforming growth factor-ß (TGF-ß) are critical in initiating pro-inflammatory responses, and the serum levels of those cytokines may be involved in the pathophysiology of ß-thalassemia (ß-thal). To assess this hypothesis, we studied 23 pediatric patients with ß-TM by measuring serum levels of IL-4, IL-8, IL-13 and TGF-ß, as well as evaluating infection frequency per year, total number of transfusions and serum ferritin (SF) levels, together with age-matched healthy controls. We found that patients with ß-thal had higher IL-8, IL-13 and TGF-ß concentrations than normal controls, whereas markedly decreased serum IL-4 level was documented in patients with ß-TM. Serum IL-4 level of ß-thal patients showed a negative significant correlation with infection frequency, total number of transfusions and SF levels. On the contrary, serum levels of IL-8, IL-13 and TGF-ß exerted a positive relationship with those clinical parameters. Taken together, our study implies that dysregulated cytokine profile might contribute to iron overloads and impair immune cell functions, thus serving as useful biomarkers for diagnosis and evaluation of ß-TM in the future. Our study sheds new light on the pathogenesis of ß-TM.

[Relationship between IKZF3 Gene Single Nucleotide Polymorphisms and Childhood Acute Lymphoblastic Leukemia].

OBJECTIVE: To investigate the relationship between single nucleotide polymorphisms (SNPs) of IKAROS family Zinc finger 3 (IKZF3) gene and the risk of acute lymphoblastic leukemia (ALL) in children. METHODS: The peripheral blood samples from 286 children with ALL and 382 healthy children were collected and divided into ALL group and control group, respectively. The genotypes of IKZF3 gene at rs62066988 C > T and rs12946510 C > T were detected by quantitative PCR with TaqMan detection system, and their correlation with ALL was analyzed. RESULTS: The distribution frequencies of CC, CT and TT genotypes at rs62066988 in ALL group were 58.39%, 37.06% and 4.55%, respectively, while those in control group were 69.19%, 27.68% and 3.13%, respectively. The distribution frequencies of CC, CT and TT genotypes at rs12946510 in ALL group were 58.16%, 34.75% and 7.09%, respectively, while those in control group were 55.76%, 37.43% and 6.81%, respectively. Compared with the control group, the distribution frequency of CT/TT genotype at rs62066988 was significantly increased in the ALL group (OR=1.59, 95%CI: 1.16-2.19, P=0.004). However, there was no significant difference in the distribution of rs12946510 C > T polymorphism between ALL group and control group. CONCLUSION: The CT/TT genotype of IKZF3 at the site of rs62066988 is associated with the increased risk of ALL in children.

[Down-Regulation of MiR-125b Reverses Drug Resistance of Doxorubicin-Resistant Leukemia Cells].

OBJECTIVE: To investigate whether the down-regulation of miR-125b can reverse the drug-resistence of doxorubicine-resistant leukemia cell lines or not, so as to explore a new method for treatment of drug-resistant leukemia patients. METHODS: The expression levels of miR125b in doxorubicine drug-sensitive and doxorubicine drug-resistant leukemia cell lines.HL-60, K562 and HL-60/Dox, the K562/Dox were detected by using RT-qPCR; the up-regulation or inhibition of miR-1256 expression in HL-60/Dox were performed by electroporation transfection, then the viability of cells treated with doxorubicine of different concentration was detected by CCK-8 method, the proliferation inhibition curve of cells was drawed, and the IC50 was calculated. RESULTS: The miR-125b expression was obviously up-regulated in drug-resistant cell lines HL-60/DOX and K562/DOX, as compared with HL-60 and K562 cell lines. The miR-125b expression level in HL-60/DOX and K562/DOX cells was 15 times and 5 times higher than that in HL-60 and K562 cells, respectively. The up-regulating or inhibiting expression of miR-125b in HL-60/DOX cells found that the proliferation inhibition rate in cells transfected with miR-125b mimic significantly decreased, compared with control group (P<0.01), while the proliferation inhibition rate in cells transfected with miR-125b inhibitor significantly increased, compared with control group(P<0.01). CONCLUSION: The miR-125b expression in HL-60/Dox and K562/Dox cells has been up-regulated, down-regulation of miR-125b expression can reverse the drug resistance of leukemia cells to doxorubicine.

[Expression of miR-181a in Acute Myeloid Leukaemia and Its Effect on Cell Proliferation].

OBJECTIVE: To investigate the expression of miR-181a in AML cell lines and explore its effect on cell proliferation. METHODS: The expression of miR-181a in AML cell lines (NB4,HL-60,K562 and MV-4-11) was detected by quantiative polymerase chain reation(qPCR). Moreover, the cell proliferation and cell cycle were evaluated in several cell lines (HL60, NB4 and K562) by using CCK-8 and flow cytometry after the imitative transfection with miR-181a. RESULTS: The miR-181a expression was significantly increased in most AML cell lines, including NB4,HL-60 and MV-4-11, but decreased in a few AML cell lines(K562), as compared with that in control(P<0.05). Overexpressed miR-181a in the cell lines significantly enhanced the cell proliferation, as well as the cell ratio of S-to and G2-phase by miR-181a imitative transfection in vitro. CONCLUSION: Overexpression of miR-181a can promote AML cell proliferation. MiR-181a may play an oncogene role in AML, studying the MiR-181a may provide a new method for treatment of AML.

[MiR-181a Promotes Proliferation of Human Acute Myeloid Leukemia Cells by Targeting ATM].

OBJECTIVE: To investigate miR-181a function and regulation mechanism by identifying miR-181a target genes in acute myeloid leukemia (AML). METHODS: The HL-60 cells of human AML was transfected by small molecular analog miR-181a, the cell proliferation was detected by CCK-8 method after electroporation in HL-60 cell lines. Target genes of miR-181a were predicted and analyzed by the bioinformatics software and database. Target genes were confirmed by HL-60 cell line and the patient leukemia cells. RESULTS: Overexpressed miR-181a in HL-60 cell line significantly enhanced cell proliferation compared with that in control (P < 0.05). Dual luciferase reporter gene assay showed that miR-181a significantly suppressed the reporter gene activity containing ATM 3'-UTR by about 56.8% (P < 0.05), but it didn't suppress the reporter gene activity containing 3'-UTR ATM mutation. Western blot showed that miR-181a significantly downregulated the expression of ATM in human leukemia cells. It is also found that miR-181a was significantly increased in AML, which showed a negative correlation with ATM expression. CONCLUSION: miR-181a promotes cell proliferation in AML by regulating the tumor suppressor ATM, thus it plays the role as oncogene in pathogenesis of AML.

[miR-125b promotes proliferation of human acute myeloid leukemia cells by targeting Bak1].

OBJECTIVE: To investigate miR- 125b regulation mechanism by identifying miR-125b target genes and its function in acute myeloid leukemia (AML). METHODS: The bioinformatics software and database were applied to predict and analyze target genes of miR-125b. The vector contained the target gene 3'-UTR portion cloned into a luciferase reporter construct. A luciferase reporter assay was performed following co-transfection of small molecular miR-125b mimics and target gene wild-type or mutant plasmid into HEK-293T cells. Further in leukemia cell lines NB4 and HL-60, the protein level of target gene was measured by Western blot after overexpression miR-125b. Finally, the viabilities of NB4 and HL-60 cells were measured by CCK-8 assay at 24 h, 48 h, 72 h, 96 h after electroporation. RESULTS: Bcl-2-antagonist/killer 1 (Bak1), a pro-apoptotic gene, was a target gene of miR-125b by software predicts. Reporter vector containing the 3'-UTR Bak1 wild and mutation sites were co-transfected with small molecule analogues of miR-125b in HEK-293T cells. Dual luciferase reporter gene assay system showed that miR-125b significantly suppresses the reporter gene activity containing Bak1 3'-UTR by about 53.8% (P<0.05), but it didn't suppresses the reporter gene activity containing 3'-UTR Bak1 mutation. Western blot showed that miR-125b mimics significantly down-regulated the expression of Bak1 in human leukemia cell lines NB4 and HL-60. Meanwhile, the growth rate of cells treated with miR-125b obviously increased compared with that in control by CCK-8 test (P<0.05). CONCLUSION: Our findings strongly indicated that BAK1 was a downstream target gene of miR-125b, and miR-125b promoted proliferation in human AML cells at least partially by targeting Bak1, so we speculated that miR-125b as an oncogene could be a potential therapeutic target for treating AML.